Method of making ammunition having a two-piece primer insert

[0010]The insert joint may be smelted, sintered, adhesive bonded, laser welded, ultrasonic welded, friction spot welded, or friction stir welded. The upper primer insert portion, the lower primer insert portion or both may be independently formed by metal injection molding, polymer injection molding, stamping, milling, molding, machining, punching, fine blanking, smelting, or any other method that will form insert portions that may be joined together to form a primer insert. The upper primer insert portion, the lower primer insert portion or both independently comprises a polymer, a metal, an alloy, or a ceramic alloy. The upper primer insert portion and the lower primer insert portion may be made of the same material or different materials. The upper primer insert portion comprises a polymer, a metal, an alloy, or a ceramic alloy and the lower primer insert portion comprises different polymer, metal, alloy, or ceramic alloy. The upper primer insert portion and the lower primer insert portion may be made from stainless steel or brass. The primer insert may include a flash hole groove that extends circumferentially about the upper primer aperture or the lower primer aperture. The first polymer composition, the second polymer composition or both comprise a nylon polymer. The first polymer composition, the second polymer composition or both comprise between about 10 and about 70 wt % glass fiber fillers, mineral fillers, or mixtures thereof. The first polymer composition, the second polymer composition or bot

Conventional ammunition cartridge casings for rifles and machine guns, as well as larger caliber weapons, are made from brass, which is heavy, expensive, and potentially hazardous.

Plastic cartridge casings have been known for many years but have failed to provide satisfactory ammunition that could be produced in commercial quantities with sufficient safety, ballistic, handling characteristics, and survive physical and natural conditions to which it will be exposed during the ammunition's intended life cycle; however, these characteristics have not been achieved.

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